Contractors should always take the time to price out the
risk properly. Even in an ideal scenario, with adequate subsurface
information available to the contractors and plenty
of time to properly analyze the information, contractors
often end up assessing the risk and then price it in their bid.
Competitive bidding does not necessarily result in a lower
bid or full transfer of the risk. Without proper investigation
and a short bidding period, there will always be a limited
understanding of the scope of the risk by the contractor. The
contractor will either 1) accept the risk by throwing money at
it, 2) ignore the risk and claim later or 3) refuse to bid due to
unacceptable risks.
Often early geotechnical
investigations do not encapsulate
the full intention of the
project scope as it may still be
in development.
Pile Driving
Analyzer® (PDA)
to retain only the most qualified geotechnical firms to provide
quality early pre-bid data. Quality of geotechnical data
is influenced by procurement method for geotechnical services,
which significantly affects risks in construction and
overall project cost. It has been proven that going the cheap
route when it comes to geotechnical investigation services
simply costs owners more in the end.
A properly planned multi-phased investigation with a
budget from 0.5 per cent to 2.2 per cent of the project cost
is proven by historical evidence to be effective on most projects.
It’s also important to build in contingency costs for the
effects of phased information unearthing something unforeseen
or changes along design development warranting
further investigation.
Savings in the bid price have been achieved four to 15
times the cost of a thorough and proper geotechnical investigation.
Remember, in the end you pay for a site investigation
whether you have one or not.
If a decent investigation is not conducted, you will pay for
it through overly conservative design, construction delays,
contractor claims, and of course, lawyers. Eventually litigation
costs end up being much higher than the cost of initially
hiring competent engineers and conducting a proper geotechnical
investigation.
In closing, remember, don’t be afraid of risk, just give projects
the due diligence they deserve. When people in all areas
of a project work together to mitigate the risks involved,
everyone wins.
Masoud Manzari is a senior geotechnical and hydrogeological
engineer with over 23 years of experience and has been involved
in a wide range of civil engineering projects, specifically for
structures built on challenging soil sites.
Mark Tigchelaar is president and founder of GeoSolv Design/
Build Inc. Tigchelaar is a licensed engineer in both Ontario and
Alberta, chair of the industry Advisory Board of York University,
and the past chair of the Canadian Geotechnical Society-
Southern Ontario section.
Pile Dynamics’ PDA:
The PDA is a high strain, dynamic load testing, and pile driving monitoring
system. This versatile device can be used to perform dynamic load testing on
most types of deep foundations. The system can be customized to best suit
your project, with cabled and wireless options.
To learn more about PDA, visit www.pile.com.
TECHNICAL
The balance of court decisions dealing with changed soil
conditions demonstrates that site investigation clauses in
contracts are not always upheld. The majority of changed
soil condition cases are settled without going to court and
owners eventually pay a penalty. Among the cases that go to
court, the success rate for owners is around 40 per cent.
In conclusion, geotechnical risk can certainly be minimized,
shared, transferred or accepted, but it cannot be
ignored or ever eliminated. Each and every project is unique
and requires specific planning for a cost-effective and thorough
geotechnical investigation, coupled with background
research on the site and surrounding area.
Scale or cost of the investigation are not the only issues in
determining the effectiveness of a geotechnical investigation.
The best way for the owner to manage geotechnical risk is
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